Review of two-phase flow instability

Bouré, J. A.; Bergles, A. E.; Tong, Liyong

doi:10.1016/0029-5493(73)90043-5

Cited by 756 publications

(262 citation statements)

References 12 publications

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“…The density wave oscillation is the results of fluid waves of alternately higher and lower density mixtures due to multiple regenerative feedbacks among the flow rate, vapour generation rate and pressure drop [7]. In the present experiment, the density wave oscillation is observed from very small mass flow rate to large mass flow rate.…”

Section: Experimental Measurementsupporting

confidence: 43%

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Two-phase flow instabilities in horizontal straight tube evaporator

Liang

Shao

Tian

et al. 2011

Applied Thermal Engineering

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Abstract:It is essential to ensure the stability of a refrigeration system if the oscillation in evaporation process is the primary cause for the whole system instability. This paper is concerned with an experimental investigation of two phase flow instabilities in a horizontal straight tube evaporator of a refrigeration system. The relationship between pressure drop and mass flow with constant heat flux and evaporation pressure is measured and determined. It is found that there is a negative slope section in the middle of positive slope pressure drop versus mass flow velocity thus making the velocity a multi-valued function of pressure drop.Three types of dynamic instabilities including the density wave instability, pressure drop instability and thermal instability are found under the conditions of heat flux from 5 to 17 kW/m 2 , mass velocity from 150 to 1500 kg/(m 2 ·s), and evaporating pressure from 0.5 to 0.8 MPa. The density wave oscillation occurs at almost all mass velocities; its period is about 1~3 seconds and its amplitude is the lowest. The pressure drop oscillation takes place in a negative slope section; its period is about 10 seconds. The thermal oscillation can be induced at a high mass flow velocity, and its period is of 60 seconds and the amplitude is the highest among the † Corresponding

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Section: Experimental Measurementsupporting

confidence: 43%

“…instability and flow pattern transition instability; the dynamic instability, initiated by the transient changes in boiling process, mainly covers the density-wave oscillations, thermal oscillations and pressure drop oscillations [7,8].…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Two-phase flow instabilities in horizontal straight tube evaporator

Liang

Shao

Tian

et al. 2011

Applied Thermal Engineering

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“…high power and low flow rate). Bouré et al [21] and Durga Prasad et al [22] presented a classification of the different types of instabilities and an overview of earlier work. A static instability (flow excursion, the so called Ledinegg instability) can be described using only the steady-state equations.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of the coupled thermo-hydraulic–neutronic stability of a natural circulation HPLWR

T’Joen

Rohde

2012

Nuclear Engineering and Design

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The HPLWR (High Performance Light Water Reactor) is the European concept design for a SCWR (SuperCritical Water Reactor). This unique reactor design consists of a three pass core with intermediate mixing plena. As the supercritical water passes through the core, it experiences a significant density reduction. This large change in density could be used as the driving force for natural circulation of the coolant, adding an inherent safety feature to this concept design. The idea of natural circulation has been explored in the past for boiling water reactors (BWR). From those studies, it is known that the different feedback mechanisms can trigger flow instabilities. These can be purely thermo-hydraulic (driven by the friction -mass flow rate or gravity -mass flow rate feedback of the system), or they can be coupled thermo-hydraulic -neutronic (driven by the coupling between friction, mass flow rate and power production). The goal of this study is to explore the stability of a natural circulation HPLWR considering the thermo-hydraulic -neutronic feedback. This was done through a unique experimental facility, DeLight, which is a scaled model of the HPLWR using Freon R23 as a scaling fluid. An artificial neutronic feedback was incorporated into the system based on the average measured density. To model the heat transfer dynamics in the rods, a simple first order model was used with a fixed time constant of 6 seconds. The results include the measurements of the varying decay ratio (DR) and frequency over a wide range of operating conditions. A clear instability zone was found within the stability plane, which seems to be similar to that of a BWR. Experimental data on the stability of a supercritical loop is rare in open literature, and these data could serve as an important benchmark tool for existing codes and models.

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“…Many research results have shown that increasing the inlet resistance coefficient or pressure drops in singlephase region will make the system become more stable< 3 ), that is to say, the stable region located on the small inlet subcooling side becomes larger and larger with the increase of the inlet resistance coefficient. The experimental results from the HRTL-200 certified this and were shown in Fig.…”

Section: (1) Inlet Subcooling and Flow Instabilitymentioning

confidence: 99%

Thermalhydraulic Investigation Using a Test Facility Simulating 200 MW Integral Heating Reactor

Jia

et al. 2000

Journal of Nuclear Science and Technology

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Review of two-phase flow instability

Cited by 756 publications

References 12 publications

Two-phase flow instabilities in horizontal straight tube evaporator

Two-phase flow instabilities in horizontal straight tube evaporator

Experimental study of the coupled thermo-hydraulic–neutronic stability of a natural circulation HPLWR

Thermalhydraulic Investigation Using a Test Facility Simulating 200 MW Integral Heating Reactor

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